As computerization develops and office automation as well as factory automation progress in every field, the problem has been posed in Japan and Western countries that the degree of fatigue experienced by operators who are engaged in VDT operation is higher than that of clerical employees who are engaged in general office work and VDT operations pose a stronger risk of causing illness. The illnesses that have been reported include:
1. Symptoms related to the eyes PA1 2. Symptoms related to the organs of locomotion PA1 3. Spiritual symptoms PA1 4. Skin symptoms PA1 5. Abnormality of reproductions. PA1 (i) Fatigue or strain of the eyes and physical disorder and feelings of displeasure around peripheral portions of the eyes, and PA1 (ii) Abnormality of the eyesight such as deterioration of eyesight, an object is seen as a doubled image and images become dim. PA1 (i) Taking a rest after operation for a fixed time. PA1 (ii) Illumination of a working place. PA1 (iii) Using office furniture such as a working table giving due regard to an operator's posture. PA1 (iv) Putting into effect a health diagnosis. PA1 Of course, the foregoing points of improving a work environment are important, but there are differences between individuals as far as operators working in the operations are concerned, and at present, there is no decisive countermeasure.
The symptoms relating to the eyes in connection with the new technologies related to this invention will be described in the following in detail.
These reports are made by the following institutions: Report of National Labor Safety and Hygiene Institute of Sweden, 1973.
Report of London University, England, 1978.
Report of Studies of Cakir of West Berlin University, 1978.
Report of National Labor Safety and Hygiene Institute of of USA, 1980.
Report of Studies of Elias of France, 1980.
In Japan, a report published in the edition of May 2, 1983 of Nikkei Computer Magazine set forth the results of an inquiry investigation conducted by the magazine to users of computers in 1983. There were responses from 2,101 persons who, and excluding 86 persons responded as non-operators of the VDT, in the responses of symptoms of which the patients were conscious, of the 2,015 VDT users, 69.2% complained about fatigue of the eyes, 39.6% complained about fatigue of the nape, 25.3% complained about strain of the eyes, and 22.0% complained about obscure vision of an object once in a while. Complaints about symptoms of the eyes ranked high.
As countermeasures against these symptoms, the following actions are considered in Japan and Western countries.
The VDT operations by an operator of a computer are classified into a data input operation in which data is inputted while viewing various kinds of slips and manuscripts which are coded by characters, digits, classification symbols with attention to characters, digits, drawings and the like displayed on a display screen, and a dialogic operation with the computer which takes place while viewing data displayed on the display screen upon calling information inputted to the computer by the operation of a keyboard and a new data manuscript for newly classifying and amending the data.
In order to perform these operations, the operator is required to view the three portions comprising an information display device (display screen), an information input device (keyboard) and an information source (slips or manuscripts for input). The photowaves converted from electronic signals representing characters, drawings and the like on the display screen enter the naked eyeballs of the operator, and are concentrated in yellow spot sections of their eyeballs, and the operator is required to use the optic nerves to the utmost limit in the process of reading and understanding the display.
However, since the electronic waves repeat strong and weak fluctuations in each instant, the brightness of the electronic display is not equalized, and the display fluctuates and vibrates steadily which is not stable and moreover, infrared rays and ultraviolet rays generated from the display screen enter the eyeballs of the operator.
When they are composite, they constitute the causes for asthemnopia, weakening of the eyesight and exhaustion of the physical strength.
The three portions (information display device, information input device and information source) to which the operator gases steadily are different in the degrees (illumination) of brightness, and the human eyes have functions of automatically adjusting the bundle of rays entering the eyes by the degrees of the brightness.
In the VDT operations where the operator gases steadily to the three portions whose brightnesses are different, fatigue of the eyes such as weariness, strain, and irritation occur.